Aluminium oxide is impermeable and, unlike the oxide layers on many other metals, it adheres strongly to the parent metal. If damaged mechanically, aluminiumâs oxide layer repairs itself immediately.
Saliva helps remove oral waste and cavity-causing bacteria, protects teeth from decay by neutralizing harmful acids, and helps re-mineralize tooth enamel. Saliva also keeps oral tissues healthy by preventing infection by controlling bacteria and fungi in the mouth.
You have three pairs of saliva glands in your mouth, and they each produce a different kind of saliva. The body always knows how much saliva to produce, and what kind. Thatâs why your saliva glands will produce much more saliva when you eat a dry cracker than when you eat a juicy piece of fruit!The largest saliva glands in the mouth produce more than 25,000 quarts of saliva in an average lifetime!aliva also contains an enzyme called ptyalin, which digests food the same way that the digestive juices in your stomach do. This enzyme changes some of the starch in food into sugar, giving the stomach a âhead startâ in digesting the food.